Apparatus for checking the pull on cables in tension



W. BETTA Dec. 26, 1967 APPARATUS FOR CHECKING THE PULL ON (DA-BLISS IN TENSION Fild Sept. 25, 1966 Fig.2

United States Patent W 3,360,243 APPARATUS FOR CHECKING THE PULL 0N CABLES 1N TENSION Walter Betta, Bergamo, Italy, assignor to GRI Ofiicine Meccaniche di Prccisione S.p.A., Milan, Italy Filed Sept. 23, 1966, Ser. No. 581,596 Claims priority, application Italy, Oct. 1, 1965, 729,760 2 Claims. (Cl. 254184) ABSTRACT OF THE DISCLOSURE An apparatus for checking the pull on a cable under tension comprising at least one drum having the cable passing thereabout, a main shaft and main control assembly for imparting a driving or braking couple to the drum. The drum including an externally toothed ring gear engaging with a pinion which is coaxial with the main shaft. The apparatus including means for transmitting force between the main shaft and the pinion.

This invention relates to the continuous checking of the pull on cables in tension, particularly for the stringing of high voltage electric power lines.

It is known that in modern systems for stringing high voltage electric power lines the conductors, which may be single or multiple, are stretched by a continuous tension that maintains them uniformly raised from the ground. Since the stringing i generally effected over lengths of several kilometres it is absolutely essential that it should be effected in a very uniform manner, according to the requirements of the project, and to prevent the line from being subjected to undesirable stresses.

With this object, an apparatus has already been provided which permits direct and continuou reading of the tensile force applied to the cables, thus permitting the operators to attend at the right time to the adjustment of he apparatus for controlling the stringing.

An apparatus provided with this object is the subject, for example, of Italian Patent No. 570,273, and comprises essentially a frame which is mounted on the cable in tension and is associated with means that provide the value of the pull resulting from the curvature of the cable. Although this apparatus provides a sufficiently exact indication of the pull, it is however somewhat complicated to assemble and use.

In accordance with the present invention there is rovided a reading apparatus which is extremely simple and practicable, associated directly with the tension controlling and adjusting assembly, which may be either the tensioning winch or the brake, and which obtains the value of the pull from the value of the couple that is exactly exerted by the tensioning and/or braking assembly. Such apparatus, which is applicable to an assembly in which there is provided at least one adhesion drum on which is wound at least one cable in tension and a main control assembly for transmitting a motive or braking couple to the drum via at least one pinion, is characterized substantially by the feature that the main shaft of the control assembly and the pinion are coaxial. A reduction gear box adapted to transmit the motion of the shaft to the pinion, the gear box is also rotatably mounted on the common axis and is having an external projection adapted to bear on a fixed dynamometric body.

An embodiment of the invention will now be described with reference to the accompanying drawing, in which FIG. 1 is a diagrammatic side view and 3,360,243 Patented Dec. 26, 1967 FIG. 2 is a diagrammatic plan view of an apparatus according to the present invention.

As shown in the drawing, the apparatus comprises a pair of adhesion drums 1 and 2 mounted on a rigid framework 3 by means of pins 4 and 5, respectively, so as to be freely rotatable. One or more cables in tension wind on to the drums 1 and 2. Such apparatus may be, as desired, a tensioning winch or a brake, there being in both cases the possibility of adjusting the tensile force applied to the cable.

With the drums 1 and 2 are associated toothed rings 1' and 2' respectively, with which a pinion 6 engages. This pinion is hollow and is rotatably mounted directly on the shaft 7 which is the main shaft of the driving or braking control assembly of the apparatus. The pinion 6 is also solid with a toothed wheel 8 via a cylindrical prolongation 6', whilst a second toothed wheel 9 is solid with the end 7 of the shaft 7. Between the toothed wheels 8 and 9 is provided a series of reduction gears 10, 11, 12 and 13 the pins of which are mounted within a rigid box 14. The latter is in its turn rotatably mounted on the same axis x-x as the haft 7 by means of bushings and bearings mounted on the cylindrical prolongation 6' and on the end 7' of the shaft 7 respectively.

The box 14 is provided externally with a projection 15 via which it can bear on the dynarnometer 16 which is fixedly mounted on the rigid framework 3.

When a couple is applied to the shaft 7, whether it is a driving couple or a braking couple, adapted to become translated via the drums 1 and 2 into a tensile force on the cables (not illustrated) then owing to the particular arrangement of the gears 9 to 13 and of the box 14 the latter tends to rotate around the axis xx. This rotation is however impeded by the bearing of the projection 15 on the dynamometer 16, which is suitably calibrated and gives a precise indication of the applied couple and hence of the tensile force that it exerts on the cables.

What I claim is:

1. An apparatus for continuously checking the pull on cables under tension, particularly for the stringing of high voltage electric power lines, comprising at least one adhesion drum on which is wound at least one cable under tension, a toothed ring fixedly attached to said drum, a pinion engaging said toothed ring, a main shaft and a main control assembly, for selectively imparting driving and braking couples to said drum through said main shaft, said main shaft and said pinion being coaxial, and means for transmitting motion between said main shaft and said pinion including a member for sensing the couple applied to said shaft.

2. An apparatus according to claim 1 in which said means for transmitting motion comprises a reduction gear box, a series of gears within said gear box adapted to transmit the motion from said shaft to said pinion, said box being rotatably mounted about an axis common to the shaft and the pinion, an external projection on the gear box and a fixed dynamometric body, said projection bearing on said dynamometric body forming said memher for sensing the couple.

References Cited UNITED STATES PATENTS 3,015,473 1/1962 Frellseri 254-172 3,261,591 7/1966 Campbell 254 172 EVON C. BLUNK, Primary Examiner.

H. C. HORNSBY, Assistant Examiner. 

1. AN APPARATUS FOR CONTINUOUSLY CHECKING THE PULL ON CABLES UNDER TENSION, PARTICULARLY FOR THE STRINGING OF HIGH HENSION DRUM ON WHICH IS WOUND AT LEAST ONE CABLE UNDER TENSION, A TOOTHED RING FIXEDLY ATTACHED TO SAID DRUM, A PINION ENGAGING SAID TOOTHED RING, A MAIN SHAFT AND A MAIN CONTROL ASSEMBLY, FOR SELECTIVELY IMPARTING DRIVING AND BRAKING COUPLES TO SAID DRUM THROUGH SAID MAIN SHAFT, SAID MAIN SHAFT AND SAID PINION BEING COAXIAL, AND MEANS FOR TRANSMITTING MOTION BETWEEN SAID MAIN SHAFT AND SAID PINION INCLUDING A MEMBER FOR SENSING THE COUPLE APPLIED TO SAID SHAFT. 